Superconducting magnet assembly

Patent metadata

Field	Value
Publication number	US-11404191-B2
Application number	US-201816762359-A
Country	US
Kind code	B2
Filing date	Oct 29, 2018
Priority date	Nov 14, 2017
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

A superconducting magnet arrangement comprises a field coil assembly with coil windings that when in operation are electrically superconducting. The field coil assembly is circuited between connection ports for a voltage supply. A switching module switches a sub-section of the field coil assembly's coil windings between its electrical superconducting and electrical resistive states, said sub-section forming a switching coil circuited between the connection ports. In the operational state where both the switching coil and the field coil(s) are superconducting and carry a permanent electrical current, the field coil(s) and the switching coil together generate a stationary magnetic field. According to the invention the switch windings give a significant contribution to the magnetic field. The field coil assembly's coil windings that may be switched between it electrically superconducting and resistive states form the switching coil. That is, the switching coil forms part of the field coil assembly and contributes significantly to the magnetic field generated by the field coil assembly.

First claim

The invention claimed is:

1. A superconducting magnet arrangement comprising:
a field coil assembly configured to generate a stationary magnetic field in an operational state, the field coil assembly including (i) coil windings that are electrically superconducting when the field coil assembly is in the operational state, and (ii) connection ports for voltage supply, wherein the coil windings are circuited between the connection ports; and
a switching module configured to switch a switchable section of the coil windings between an electrical superconducting state and an electrical resistive state, wherein the switchable section of the coil windings forms a switching coil circuited between the connection ports and remaining sections of the coil windings form at least one field coil of the field coil assembly,
wherein in the operational state the switching coil and the at least one field coil operate together to generate the stationary magnetic field.

2. The superconducting magnet arrangement of claim 1 , wherein inductance of the switching coil is smaller than inductance of the at least one field coil.

3. The superconducting magnet arrangement of claim 2 , wherein a ratio of the inductance of the switching coil to the inductance of the at least one field coil is in a range of 1/20 to 1/2.

4. The superconducting magnet arrangement of claim 3 , wherein the ratio of the inductance of the switching coil to the inductance of the at least one field coil is in a range 0.08 to 0.12.

5. The superconducting magnet arrangement of claim 1 further comprising a support structure which carries the field coil assembly, wherein a thermal isolation is provided between the switching coil and the support structure.

6. The superconducting magnet arrangement of claim 1 , wherein, when in the electrical superconducting state, the switching coil is circuited in series with the at least one field coil.

7. The superconducting magnet arrangement of claim 1 , wherein the at least one field coil comprises multiple field coils arranged coaxially along a common longitudinal axis, coil windings of the multiple field coils and the switching coil are azimuthally around the common longitudinal axis.

8. The superconducting magnet arrangement of claim 1 , wherein the at least one field coil and the switching coil include windings of a high-temperature superconducting material having a critical temperature in a range of 20-80K.

9. The superconducting magnet arrangement of claim 8 , wherein the high-temperature superconducting material is MgB 2 .

10. A magnetic resonance imaging system comprising the superconducting magnet arrangement as claimed in claim 1 .

11. The superconducting magnet arrangement of claim 1 , wherein the switching module comprises a heater configured to heat the switchable section of the coil windings to switch the switchable section of the coil windings from the electrical superconducting state to the electrical resistive state.

12. The superconducting magnet arrangement of claim 11 , wherein the heater is configured to deactivate, allowing the switchable section of the coil windings to cool, to switch the switchable section of the coil windings from the electrical resistive state to the electrical superconducting state.

13. The superconducting magnet arrangement of claim 1 , wherein in the operational state, electrical currents in the switching coil and the at least one field coil become equal.

14. A superconducting magnet arrangement comprising:
a field coil assembly including (i) coil windings that are electrically superconducting when in operation and (ii) connection ports for voltage supply, wherein the coil windings are circuited between the connection ports; and
a switching module configured to switch a switchable section of the coil windings between an electrical superconducting state and an electrical resistive state, wherein the switchable section of the coil windings forms a switching coil of the field coil assembly,
wherein the switching coil includes a length of superconducting wire in a range of 1600-2400 m.

15. The superconducting magnet arrangement of claim 14 , wherein the coil windings include a high-temperature superconducting material having a critical temperature in a range of 20-80K.

16. The superconducting magnet arrangement of claim 15 , wherein the high-temperature superconducting material is MgB 2 .

17. A method of ramping-up a field coil assembly of a superconducting magnet arrangement, the field coil assembly comprising a plurality of coil windings including a switching coil and at least one field coil, the method comprising:
setting the switching coil to a resistive state and connecting a voltage supply to connection ports of the field coil assembly to increase an electrical current through the at least one field coil;
when the electrical current through the at least one field coil has reached a pre-set end-value for the at least one field coil to be electrically superconducting, setting the switching coil to a superconductive state for the switching coil to be electrically superconducting; and
switching-off the voltage supply,
wherein, when electrically superconducting, the switching coil and the at least one field coil operate together to generate a stationary magnetic field.

18. The method of claim 17 , wherein setting the switching coil to the resistive state comprises heating the switching coil.

19. The method of claim 17 , wherein setting the switching coil to the resistive state comprises interrupting cooling of the switching coil.

20. The method of claim 17 , wherein inductance of the switching coil is smaller than inductance of the at least one field coil.

Assignees

• Koninklijke Philips Nv

Inventors

• Overweg Johannes Adrianus

Classifications

• H01F6/008

  Electric circuit arrangements for energising superconductive electromagnets · CPC title

• G01R33/3815

  with superconducting coils, e.g. power supply therefor · CPC title

• H01F6/006

  Supplying energising or de-energising current; Flux pumps · CPC title

• H01F6/06 Primary

  Coils, e.g. winding, insulating, terminating or casing arrangements therefor · CPC title

• Y02E40/60

  Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment · CPC title